Two related projects are proposed as part of an application for a Research Career Development Award. First, it is suggested that information about the evolution of patients' symptoms during recovery from aphasia will provide an important source of constraint on the postulation of explanatory models to account for particular aphasis syndromes. Three separate experimental batteries are developed to investigate the nature of the underlying deficit in agrammatic Broca's aphasia, conduction aphasia and anomic aphasia. Specific hypotheses are developed concerning the possible relationships among co-occuring symptoms and their underlying basis. Patients meeting the selection criteria will be tested at several intervals over the course of the first year post-onset using one of the experimental batteries. A second project is proposed to develop a computer-based system for the simulation and classification of reading and writing errors produced by dyslexic and dysgraphic patients. This system will focus on the classification of errors involving the translation between graphemes and phonemes, and is intended to investigate the incidence of errors that are related to grapheme-to-phoneme or phoneme-to-grapheme conversion.